Hi am jamil i would like to get details on project proposal on signal denoising ..My friend Justin said project proposal on signal denoising will be available here and now i am living at ......... and i last studied in the college/school ......... and now am doing ....i need help on ......etc
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The threshold is a technique used for the elimination of signal and image. The discrete wavelet transform uses two types of filters: (1) average filters and (2) detail filters. When we decompose a signal using the wavelet transform, we are left with a set of wavelet coefficients that correlates with the high frequency subbands. These high frequency subbands consist of the details of the data set. If these details are small enough, they could be omitted without substantially affecting the main features of the data set. In addition, these small details are often those associated with noise; Therefore, by setting these coefficients to zero, we are essentially killing the noise. This becomes the basic concept behind the threshold-set all the subband coefficients of the frequency which are less than a particular threshold to zero and use these coefficients in an inverted wave transformation to reconstruct the data system.
In a joint work with Andrew Bruce (MathSoft, Seattle) and Sylvain Sardy (EPFL, Lausanne), we developed numerical methods for signal deletion using the wavelet base. The problem was reformulated as an optimization problem (in fact, a convex quadratic program with special structures) and a block coordinate relaxation method (Gauss-Seidel) was applied as well as a dual-primary interior point method to its solution .
The general replacement procedure involves three steps. The basic version of the procedure follows the steps described below:
• Decompose: Choose a wavelet, choose a level N. Calculate the wavelet decomposition of the signal at the N level.
• Threshold Detail Coefficients: For each level from 1 to N, select a threshold and apply a soft threshold to the detail coefficients.
• Reconstruction: Calculates the reconstruction of the wavelet using the original N-level approximation coefficients and the modified detail coefficients of the levels from 1 to N.
There are two points to be addressed in particular:
• how to choose the threshold,
• and how to make the threshold.